FAILED: patch "[PATCH] RDMA/uverbs: Check port number supplied by user verbs cmds" failed to apply to 4.4-stable tree

The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From: Boris Pismenny <[email protected]>
Date: Tue, 27 Jun 2017 15:09:13 +0300
Subject: [PATCH] RDMA/uverbs: Check port number supplied by user verbs cmds

The ib_uverbs_create_ah() ind ib_uverbs_modify_qp() calls receive the port number from user input as part of its attributes and assumes it is valid. Down on the stack, that parameter is used to access kernel data structures. If the value is invalid, the kernel accesses memory it should not. To prevent this, verify the port number before using it.

BUG: KASAN: use-after-free in ib_uverbs_create_ah+0x6d5/0x7b0
Read of size 4 at addr ffff880018d67ab8 by task syz-executor/313

BUG: KASAN: slab-out-of-bounds in modify_qp.isra.4+0x19d0/0x1ef0
Read of size 4 at addr ffff88006c40ec58 by task syz-executor/819

index 70b7fb156414..e63f2a13c5e1 100644
@@ -1931,6 +1931,11 @@ static int modify_qp(struct ib_uverbs_file *file,
 		goto out;
 	}
 
+	if (!rdma_is_port_valid(qp->device, cmd->base.port_num)) {
+		ret = -EINVAL;
+		goto release_qp;
+	}
+
 	attr->qp_state		  = cmd->base.qp_state;
 	attr->cur_qp_state	  = cmd->base.cur_qp_state;
 	attr->path_mtu		  = cmd->base.path_mtu;

@@ -2541,6 +2546,9 @@ ssize_t ib_uverbs_create_ah(struct ib_uverbs_file *file,
 	if (copy_from_user(&cmd, buf, sizeof cmd))
 		return -EFAULT;
 
+	if (!rdma_is_port_valid(ib_dev, cmd.attr.port_num))
+		return -EINVAL;
+
 	INIT_UDATA(&udata, buf + sizeof(cmd),
 		   (unsigned long)cmd.response + sizeof(resp),
 		   in_len - sizeof(cmd), out_len - sizeof(resp));